Jeremiah
Jeremiah 6:7ESV·traditional attribution

As a well keeps its water fresh, so she keeps fresh her evil; violence and destruction are heard within her; sickness and wounds are ever before me.

John Calvin Reformed @genevareformer

The Prophet enlarges on what he had said in the last verse; for he had shewn, by mentioning one kind of evil, that Jerusalem was a den of thieves, as oppression dwelt in the midst of it. But he now, by a comparison, amplifies his former statement, and says, that violence, oppression, devastation, grief, and smiting, streamed forth like waters from a fountain.

Matthew Henry Presbyterian @wholebiblehenry

Here is I. Judgment threatened against Judah and Jerusalem. The city and the country were at this time secure and under no apprehension of danger; they saw no cloud gathering, but every thing looked safe and serene: but the prophet tells them that they shall shortly be invaded by a foreign power, an army shall be brought against them from the north, which shall lay...

Commenting on Jeremiah 6:1-8

John Gill Reformed Baptist @doctorgill

As a fountain casteth out her waters,.... In great abundance, and continually: so she casteth out her wickedness; this metaphor expresses the multitude of her sins, the frequent and constant commission of them, and the source and spring of them, the corrupt fountain of the heart; see Mat 12:34, violence and spoil is heard in her; that is, the cry of those that are oppressed...